The monitoring network within this area

Hydrionis holds 2,382 values from 2 gauges within it. Discharge is a property of a gauge and its reach, not of this drainage area, so this page reports the network and its records rather than a single figure.

2

Gauges

2,382

Values held

1895–2026

Record spans

Gauges within the Upper Dolores huc8 subbasin

2 monitoring points, positioned as the publisher records them.

Flood peaks, as measured

This gauge's flood record, as measured. Unlike a daily mean it is the discharge at the moment the river was highest, which is the figure flood frequency analysis is built on.

Largest measured flow of each year at DOLORES RIVER AT DOLORES, CO.

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1896–2025.

Show relevant events (1 event)Shading marks when something was recorded, not what caused the line.

Published by the gauge's own operator from its sub-daily record; Hydrionis stores the figure rather than recomputing it. A year the gauge did not cover produces no value rather than a low one, and the gaps are stated below the chart. A peak is a property of this gauge and its reach: a larger flood upstream or downstream of it is not in this series.

What the shaded periods are (1 event)

A shaded period marks when something was recorded, not what caused the shape of the line. Where the two coincide, they coincided.

Documented record — A documented event, compiled from cited sources after it happened. The dates are as good as the record, which for older events can mean the month rather than the day.

Event	Type	Period	Standing	Authority
Hurricane Katrina water and sanitation collapse	Flood	2005-08-29 – 2005-09-30	Documented record	Compiled record

Not shown on this chart

The 1976 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
The 2022 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Yorkshire drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cantareira water crisis, São Paulo — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cape Town Day Zero — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
European drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.

View the data behind this chart

Underlying data
Period	DOLORES RIVER AT DOLORES, CO. (m³/s)
1896	44.2
1897	102
1898	59.5
1901	90.6
1902	40.2
1903	81.8
1911	283
1922	208
1923	137
1924	123
1925	159
1926	148
1927	199
1928	98.5
1929	120
1930	87.8
1931	43.6
1932	136
1933	110
1934	30.0
1935	103
1936	81.6
1937	113
1938	144
1939	51.3
1940	60.3
1941	229
1942	135
1943	113
1944	161
1945	107
1946	77.0
1947	89.5
1948	143
1949	230
1950	57.8
1951	71.4
1952	154
1953	82.1
1954	44.2
1955	65.1
1956	59.5
1957	189
1958	127
1959	47.3
1960	94.9
1961	71.4
1962	90.9
1963	56.1
1964	95.7
1965	110
1966	72.5
1967	52.7
1968	102
1969	79.9
1970	147
1971	53.8
1972	47.0
1973	163
1974	58.6
1975	130
1976	74.8
1977	16.6
1978	97.4
1979	130
1980	139
1981	53.8
1982	83.8
1983	172
1984	183
1985	123
1986	136
1987	110
1988	68.2
1989	51.3
1990	48.1
1991	64.0
1992	76.7
1993	156
1994	75.0
1995	151
1996	65.4
1997	137
1998	102
1999	99.1
2000	79.6
2001	90.3
2002	15.3
2003	60.6
2004	77.6
2005	173
2006	47.6
2008	128
2009	114
2010	92.3
2011	103
2012	42.8
2013	40.5
2014	68.2
2015	94.0
2016	85.2
2017	91.2
2018	23.6
2019	138
2020	39.1
2021	28.9
2022	63.4
2023	149
2024	43.0
2025	45.0

About this series

Everything below is a property of the data rather than a rating of it. There is deliberately no single confidence score: how much a gap matters depends on what you are about to do with the series, and only you know that.

Source	United States Geological Survey — National Water Information System · US Government work — public domain
How the values came to exist	Measured
Period held	1896–2025
Completeness	84.6% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	4 separate periods inside 1896–2025 hold no value. The longest runs from 1912 to 1921 — 10 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1896 and is not continuous from it: 130 years separate the first value from the last, and 85% of the years between them are held. The span is not the record.
Last read from the publisher	2026-10-01
Redistribution	Permitted by the upstream licences
Commercial reuse	Permitted by the upstream licences. No Hydrionis access tier can widen this.
Methodology	How this was produced

How much of the rain came back out

A discharge in cubic metres per second cannot be compared with anything: the larger number may only mean the larger catchment. Divided by the area draining to the gauge it becomes a depth of water over that land, which answers a question a reader already has — of the rain that fell here, how much came back out as river?

Water leaving the catchment above DOLORES RIVER AT DOLORES, CO., as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1896–2025.

Show relevant events (1 event)Shading marks when something was recorded, not what caused the line.

Computed by Hydrionis from the published annual mean flow and the catchment area the station's own publisher states. It is not a water balance: the difference between rainfall and runoff is not evaporation alone but also change in groundwater storage, water abstracted and taken elsewhere, and water imported by transfer schemes — which is why a catchment can yield more runoff than the rain that fell on it without anything being measured wrongly. A different area figure rescales every value here by the ratio between them.

What the shaded periods are (1 event)

A shaded period marks when something was recorded, not what caused the shape of the line. Where the two coincide, they coincided.

Documented record — A documented event, compiled from cited sources after it happened. The dates are as good as the record, which for older events can mean the month rather than the day.

Event	Type	Period	Standing	Authority
Hurricane Katrina water and sanitation collapse	Flood	2005-08-29 – 2005-09-30	Documented record	Compiled record

Not shown on this chart

The 1976 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
The 2022 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Yorkshire drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cantareira water crisis, São Paulo — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cape Town Day Zero — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
European drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.

View the data behind this chart

Underlying data
Period	DOLORES RIVER AT DOLORES, CO. (mm)
1896	165
1897	408
1898	281
1899	140
1900	170
1901	281
1902	120
1911	429
1922	453
1923	476
1924	313
1925	317
1926	503
1927	499
1928	292
1929	380
1930	277
1931	128
1932	423
1933	205
1934	89.0
1935	295
1936	276
1937	345
1938	409
1939	172
1940	216
1941	581
1942	444
1943	311
1944	420
1945	310
1946	208
1947	310
1948	349
1949	361
1950	216
1951	130
1952	467
1953	186
1954	152
1955	185
1956	183
1957	496
1958	385
1959	112
1960	267
1961	227
1962	286
1963	161
1964	184
1965	390
1966	243
1967	167
1968	279
1969	306
1970	273
1971	244
1972	190
1973	450
1974	156
1975	384
1976	228
1977	59.0
1978	307
1979	405
1980	427
1981	160
1982	360
1983	484
1984	453
1985	446
1986	453
1987	407
1988	219
1989	212
1990	148
1991	237
1992	269
1993	435
1994	222
1995	423
1996	186
1997	461
1998	297
1999	338
2000	212
2001	221
2002	69.0
2003	175
2004	238
2005	366
2006	215
2007	254
2008	345
2009	252
2010	242
2011	259
2012	141
2013	138
2014	222
2015	262
2016	265
2017	368
2018	69.0
2019	377
2020	123
2021	104
2022	172
2023	426
2024	134
2025	138

About this series

Everything below is a property of the data rather than a rating of it. There is deliberately no single confidence score: how much a gap matters depends on what you are about to do with the series, and only you know that.

Source	United States Geological Survey — National Water Information System · US Government work — public domain
How the values came to exist	Derived Computed by Hydrionis
Period held	1896–2025
Completeness	86.2% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	2 separate periods inside 1896–2025 hold no value. The longest runs from 1912 to 1921 — 10 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1896 and is not continuous from it: 130 years separate the first value from the last, and 86% of the years between them are held. The span is not the record.
Inputs last read	2026-10-01 · when the records this was computed from were last read from their publishers
Calculation date	2026-08-24 · when the calculation method was last versioned, not a reading of any publisher
Redistribution	Permitted by the upstream licences
Commercial reuse	Permitted by the upstream licences. No Hydrionis access tier can widen this.
Methodology	How this was produced

The snow standing above this water

5 automated snow stations sit inside this drainage area, weighing the snowpack rather than measuring how deep it is.

650

Fullest snowpack recorded at Lizard Head Pass, in 1993 (mm of water)

162

Thinnest, in 2026 (mm of water)

April

Month the pack is usually at its fullest

June

Month the pack has gone by, in half of years

Peak snowpack at Lizard Head Pass

Water years 1981–2026. Each point is the fullest month of that snow season.

A water year runs October to September and is named for the year it ends, so the snow of one winter stays in one point. The value is the fullest month, not the fullest day: a pack that peaked sharply mid-month reads lower here than a single measurement taken at the right moment would.

View the data behind this chart

Underlying data
Period	Lizard Head Pass (mm)
1981	255
1982	493
1983	568
1984	538
1985	496
1986	481
1987	438
1988	245
1989	329
1990	216
1991	398
1992	378
1993	650
1994	300
1995	514
1996	358
1997	570
1998	367
1999	225
2000	372
2001	339
2002	173
2003	311
2004	357
2005	440
2006	294
2007	269
2008	552
2009	426
2010	376
2011	326
2012	265
2013	266
2014	379
2015	312
2016	356
2017	536
2018	196
2019	545
2020	358
2021	305
2022	313
2023	551
2024	350
2025	300
2026	162

Read against the river

Lizard Head Pass and DOLORES RIVER AT DOLORES, CO. both sit in this drainage area, and their records overlap by 44 years. That is the span the two have in common, not a count of years both actually hold — either record may have gaps inside it. The two are shown separately rather than on one axis: millimetres of stored water and cubic metres per second are not commensurable, and a difference between them would mean nothing.

Being in the same drainage area does not put the snowpack upstream of the gauge. A subbasin is an area, and snow on one tributary can join the river below a gauge on another — so a weak relationship here may say more about which tributary was measured than about the snow.

Every gauge Hydrionis holds within this area

Gauges within the Upper Dolores and what each holds
Gauge	Measures	Values	Record
DOLORES RIVER AT DOLORES, CO.	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	372	1895–2026
DOLORES RIVER AT BEDROCK, CO	catchment area, annual maximum river flow	60	1918–2026

How these gauges were attached to this water

Assigned by the publisher to a numbered basin Every gauge here is assigned to this drainage area by its own publisher, which issues the area an official code — 14030002. A drainage area is not a river: it contains the tributaries as well as the main channel, and a gauge in it may be on any of them.

What each gauge’s link to this water rests on
Gauge	Evidence	Established
DOLORES RIVER AT DOLORES, CO.	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
DOLORES RIVER AT BEDROCK, CO	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02

What this record holds

Hydrionis decides which waters get a page, and which of those are offered to search, from what is actually held rather than from how the page reads. Five signals are counted; this record has 4 of them, which makes it a full profile.

Information-gain signals held for this water body
Signal	Held	Counts
Gauges holding a real record	2	no
Years spanned	132	yes, 20 or more
Values held	2,382	yes, 1000 or more
Distinct measurements	6	yes, 2 or more
Publishers measuring it	2	yes, 2 or more
Official identifiers	1	recorded, not counted

Use this data

Machine-readable JSON /api/v1/observations/by-subject/gauge-usgs-09166500.json
How to cite this, and who you must credit
How these figures were produced
Request this at a different scale, format or geography

No bulk download is offered here, which is a licence position rather than a product one: at least one contributing publisher does not permit redistribution. The values can be read on the page, cited, and pointed to at source.

Attribution and citation

Suggested citation for Hydrionis

Hydrionis (2026), Upper Dolores gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-upper-dolores/

Cite Hydrionis where you rely on values Hydrionis computed, on the method that produced them, or on the compilation itself. The underlying measurements remain the publishers’ and their attribution requirements apply to you directly.

Recommended, not required. Hydrionis does not claim rights over unmodified public data it relayed, and doing arithmetic on somebody else’s measurements does not make them Hydrionis’s. Cite the version and the access date: the Upper Dolores gauge records changes as publishers release and as methods are revised, and a citation without both cannot be checked later. Full guidance is on cite and reuse.

None of the contributing licences requires attribution. Crediting the publishers is still good practice and they are listed above.

Where these figures come from

MeasuredHigh confidence2025-06-05

Source: USGS — National Water Information System, USGS site 09166500, annual peak streamflow. Licence: Open.

Method: The instantaneous maximum discharge of each water year as published by USGS, dated to the day it occurred. One value per October-to-September water year; where the publisher lists both a systematic and a historic peak for a year, the larger is the annual maximum. Values the publisher marks as maximum daily averages are not held here, because they are not instantaneous peaks. Values marked as bounded rather than measured are held as censored observations carrying the bound. Cubic feet per second are converted to cubic metres per second and the publisher unit is recorded alongside.

Rating curves are extrapolated at extreme discharges, so the largest values in a peak series carry the largest measurement uncertainty. Data from the U.S. Geological Survey National Water Information System, a work of the United States government and therefore in the public domain.

Retrieved 1 October 2026.